Non-ignorable missing covariate data in survival analysis: a case-study of an International Breast Cancer Study Group trial

Summary.  Non-ignorable missing data, a serious problem in both clinical trials and observational studies, can lead to biased inferences. Quality-of-life measures have become increasingly popular in clinical trials. However, these measures are often incompletely observed, and investigators may suspect that missing quality-of-life data are likely to be non-ignorable. Although several recent references have addressed missing covariates in survival analysis, they all required the assumption that missingness is at random or that all covariates are discrete. We present a method for estimating the parameters in the Cox proportional hazards model when missing covariates may be non-ignorable and continuous or discrete. Our method is useful in reducing the bias and improving efficiency in the presence of missing data. The methodology clearly specifies assumptions about the missing data mechanism and, through sensitivity analysis, helps investigators to understand the potential effect of missing data on study results.     

Technical and vocational education and training in Uganda: A critical analysis

This article undertakes a diagnostic study of the Technical and Vocational Education and Training (TVET) sub‐sector in Uganda, with a view to characterizing the sub‐sector and identifying its potential strengths and weakness. We undertook a cross‐sectional pre‐survey of purposively selected key stakeholders in the TVET sub‐sector. We selected performance indicators following their importance in influencing the TVET reform process. Both qualitative and quantitative data was solicited from the stakeholders. Quantitative data was collected through stakeholder‐specific structured questionnaires, whilst qualitative data was collected through desk review and field visits, individual focused interviews and focus group discussions. Our findings indicate that financing and planning constraints have resulted in poor quality equipment, under‐ and ill‐trained staff, limited adoption of a competence‐based education and training (CBET) curriculum, not to mention the supervision inadequacies of TVET institutions. Besides, the limited TVET sub‐sector interaction with the private sector has incapacitated TVET curriculum development to nurture skills demanded by the private sector. Furthermore, backward technology use in the private sector has equally inhibited the success of student attachment programmes. Finally, legal ambiguities have perpetuated a qualification jungle and overlapping curricula.     

Hard thresholding regression

In this paper, we propose the hard thresholding regression (HTR) for estimating high‐dimensional sparse linear regression models. HTR uses a two‐stage convex algorithm to approximate the ?₀‐penalized regression: The first stage calculates a coarse initial estimator, and the second stage identifies the oracle estimator by borrowing information from the first one. Theoretically, the HTR estimator achieves the strong oracle property over a wide range of regularization parameters. Numerical examples and a real data example lend further support to our proposed methodology.     

Challenges of implementing restorative justice for intimate partner violence: An Islamic perspective

ABSTRACT

Intimate partner violence (IPV) is currently recognized as a critical public health concern and a human rights issue. Not surprisingly, Muslims – a religiously and socio-culturally diverse faith-based populace – are not an exception. To address this complex area of criminal justice and social policy, some scholars advocate implementing restorative justice (RJ) approaches. While RJ approaches have been traditionally used in Islamic cultures for conflict resolutions, to date, few studies have investigated how RJ operates in dealing with IPV in Muslim countries and communities. This article explores how RJ approaches towards IPV operate in some Muslim countries/communities, and offers insights into developing culturally and religiously appropriate ways of implementing RJ in IPV situations among Muslims. Given the prevalence of IPV among Muslims, the question is particularly important and timely. Taking exclusively limited examples of RJ approaches that have been used to mediate IPV cases in Muslim countries and communities, this paper found one significant challenge in the RJ approaches among Muslims: community acceptance of IPV. To reduce IPV in Muslim society, it is necessary to develop treatment models and techniques that meet cultural and religious needs. This paper found that since RJ is not alien to Islamic teachings, RJ approaches can be implemented effectively in dealing with IPV among Muslims by ensuring justice and equity of the abused woman. The findings of this paper will assist policymakers, practitioners, and service providers in providing religiously and culturally appropriate care when addressing IPV issues among Muslims.     

Age and total and free prostate-specific antigen levels for predicting prostate volume in patients with benign prostatic hyperplasia

Objectives: To investigate the predictive values of free prostate-specific antigen (fPSA), total PSA (tPSA) and age on the prostate volume.

Methods: The data of 2148 patients with lower urinary tract symptoms were analyzed retrospectively. The patients who had transrectal ultrasonography guided 10 core biopsies owing to the findings obtained on digital rectal examination and presence of high PSA levels (PSA?=?2.5–10?ng/dl), and proven to have BPH histopathologically were included in the study. Age, tPSA, fPSA and the prostate volumes (PV) of the patients were noted.

Results: One thousand patients that fulfilled the inclusion criteria were included in the study. The PV of the patients were significantly correlated with age, tPSA and fPSA (p?r?=?0.307, p?r?=?0.382, p?r?=?0.296, respectively). On linear regression model, fPSA was found as a stronger predictive for PV (AUC?=?0.75, p?p?p?=?0.013).

Conclusions: Although tPSA is an important prognostic factor for predicting PV, the predictive value of fPSA is higher. PV can easily be predicted by using age, and serum tPSA and fPSA levels.     

Environmental practices and firm performance in emerging markets: the mediating role of product quality

Environmental practices have not received as much research attention in emerging market contexts as traditional topics like quality. However, the importance of environmental practices for a firm’s production strategy has been increasing at an unprecedented level across the globe. Our research objective is, therefore, to investigate the interplay between environmental practices and quality in the pursuit of firm performance. Relying on 492 responses from Turkish manufacturers to test our hypotheses, we show that environmental practices directly improve the quality of products over and above the effect of quality management practices in emerging markets. Product quality, in turn, is important for increasing firm performance, acting as a mediator for the positive effects of environmental practices on performance. Thus, we reveal that product quality functions as an instrumental conduit between environmental practices and firm performance in emerging markets like Turkey where stakeholder pressures are weak, and regulations are often not properly enforced.     

Control‐based imputation for sensitivity analyses in informative censoring for recurrent event data

In clinical trials, missing data commonly arise through nonadherence to the randomized treatment or to study procedure. For trials in which recurrent event endpoints are of interests, conventional analyses using the proportional intensity model or the count model assume that the data are missing at random, which cannot be tested using the observed data alone. Thus, sensitivity analyses are recommended. We implement the control‐based multiple imputation as sensitivity analyses for the recurrent event data. We model the recurrent event using a piecewise exponential proportional intensity model with frailty and sample the parameters from the posterior distribution. We impute the number of events after dropped out and correct the variance estimation using a bootstrap procedure. We apply the method to an application of sitagliptin study.     

Quality_Family Deployment: A New Perspective in Determining Priority Importance for Improving Work Performance in Organization

Determining priority importance is a matter of concerns among the organization to improve their performance. One of the important aspects that should be considered by the organization is management of human resources, comprising of members who have their own family life. In this paper, we deliver a new perspective for organization to provide priority importance for their members with respect to family matters in order to inculcate the sense of belonging in the organization. To be effective in considering family matters in the organizational policy making, closer look of family characteristics are required. The idea of translating several family characteristics as quality variables and applying the quality function deployment (QFD) method to these variables could present a new way of improving the decision making in the organization by considering the process of decision in the family. Quality function deployment for family (QFDF) produces a friendly interpretation of a highly complex and intangible matters around family life; thus, making the assessment of a family easier. QFD is applied on the data gathered from a questionnaire survey based on 1,213 families in West Malaysia, Malaysia. Twelve variables are identified as voice of family, where seven of them are found to have the highest priority of importance. These variables could also be translated into quality variables in the context of organization, the strategy of improvement for the family could be interpreted as strategy for improvement in the organization. Furthermore, the results of this study provide suggestion to improve actions for managing human resource. In the discussion, three most high ranked variables from both perspectives of family and organization are considered.     

Women–Family in Quality Perspective

Bringing together women and family in quality perspective bring about interesting discussions in this paper. By integrating previous studies and considering expert opinions, we determinate the variables and dimensions with respect to women’s existence regarding their roles both in the family and at work. Many activities carried out by women represent the consumer aspects of their role. Women undertake these activities to fulfill their needs, which can be classified in the order of preference using Maslow’s Hierarchy of Need. Women success can be measured based on their ability to perform their roles successfully. We identify women’s performance by using quality approach of Personal Quality Maintenance (PQM), which is widely applied in many organizations in order to maintain the service delivery, which meets the customer satisfaction. The effort to enhance women’s satisfaction for their success in playing the multirole in the family and at work is our main consideration. This study may contribute a new point of view regarding for the women’s welfare and existence.